AW: pure functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg23285] AW: [mg23237] pure functions*From*: Klamser at t-online.de (Peter Klamser)*Date*: Sun, 30 Apr 2000 21:13:35 -0400 (EDT)*Disposition-notification-to*: "Peter Klamser" <klamser@t-online.de>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, try exli$t = Transpose[exli] MapThread[(#1 + #2) &, exli$t, 1] Regrads, Peter Klamser -----Ursprüngliche Nachricht----- Von: Helge Andersson [mailto:helgea at inoc.chalmers.se] Gesendet: Sonntag, 30. April 2000 04:05 An: mathgroup at smc.vnet.net Betreff: [mg23237] pure functions Hello, Of all the nice functions such as Map, Mapall, Thread, Apply .... I have not been able to write a simple code to generate the following procedure. I have a two dimensional list like li={{11,12,13,..},{21,22,23,...},{31,32,33,..},...} Since i like to use the pure function command I would like to map my pure function with arguments #1,#2,#3,.... on all the sublists in li. Let me exemplify with a simple pure function that add to numbers. (#1+#2)& if exli={{1,2},{3,4},{5,6},{7,8}} then I want to get the result {3,7,11,15} One solution, but not allways suitable for me, is the following (#1+#2)&[Sequence @@ Transpose[exli]]. I want to get rid of the Transpose command and if possible also making use of the /@ notation for Map. Since I have seen so many elegant examples in the mailing lists I hope I can get something out of this. Finally, When using pure functions inside Mathematica defined functions such as Select for instance, Select[{1,2,3,4,5,6},#>3&] why don't we need to specify the argument list after the &sign. I can figure out that in this case the list sent to the Select command will be used as argument list for the pure function but how does this work in general. Which are the functions where this feature is possible? /Helge -- ******************* Helge Andersson Oorganisk miljökemi CTH 412 96 Göteborg Tel. 031-772 8072 Tel. Lab. 031-55 38 67 Fax 031-772 28 53